Conventional combines include a header attached to the front of the combine vehicle. The header engages and cuts the crop as the combine vehicle travels through an agricultural field. The cut crop is then directed to the middle of the header where it is directed upwardly and rearwardly through a feederhouse. The feederhouse directs the cut crop rearwardly to the combine vehicle for further processing. The header and feederhouse are generally rigidly coupled together during operation. The feederhouse is coupled with the combine vehicle such that the feederhouse and header can pivot with respect to the combine vehicle.
Structure is provided for allowing the header and feederhouse to pivot with respect to the combine vehicle. Fixed to conventional feederhouses are a pair of laterally spaced pivot tubes. Structure at the front of the combine vehicle is provided for engaging these pivot tubes. The structure at the front of the combine vehicle serves to hold the pivot tubes while allowing the pivot tubes to pivot with respect to the combine vehicle. The feederhouse and header are thereby allowed to pivot with respect to the combine vehicle.
Some headers are automatically controlled by devices which pivot the header in response to undulations in ground contour. Headers provided with such control devices are typically pivoted relatively frequently during operation. Each time the header is pivoted with respect to the combine vehicle, the pivot tube pivots slightly within the structure that is holding it to the combine. The pivot tubes, as well as the structure at the front of the combine that holds the pivot tubes, rub against each other and tend to experience a large amount of wear due to the frequent pivoting of the header across undulating ground contours. The problem of wear is further exacerbated by the use of wider and wider headers. The wider headers weigh more than narrower headers, and therefore the greater weight of the wider headers causes even greater wear.
One type of pivot tube mechanism includes a casting having spaced apart side walls that support respective left and right ends of a pivot tube. To attach a header and feederhouse to a combine vehicle an operator drives the combine vehicle toward the feederhouse from behind until the pivot tubes are positioned within V-shaped notches formed in the front portion of the combine vehicle framework. The pivot tubes are then captured or confined in position within the notch by fixing a retainer in position across the opening of the notch. Conventional combines provide a retainer having a lower peg portion that is received within a mating opening in the lower portion of the notch. A bolt can then be tightened on the upper portion of the retainer and into a threaded opening at the top portion of the notch to thereby fix the retainer in position to effectively close the open portion of the V-shaped notch and confine the pivot tube in proper position within the V-shaped notch.
The width of the pivot tube and the spacing of the casting side walls is slightly greater than the thickness of the framework that forms the notch. This allows clearance for the framework to be inserted between the side walls of the casting and facilitates easy insertion of the pivot tube into the notch. Because the framework is narrower than the spacing of the casting side walls, the pivot tube and casting can shift laterally slightly during operation. The retainer has a width that is no greater than the width of the framework and thereby can be positioned in proper position in alignment with the peg opening and the threaded opening regardless of the lateral position of the pivot tube and casting.
It would therefore be desirable to provide a pivot tube and associated structure at the front of the combine for holding the pivot tube and that is well adapted for withstanding the frequent pivoting motion that results from use of controls that adjust the orientation of the header over undulating ground contours. It would also be desirable to provide such a mechanism that is well adapted for withstanding the increased loads associated with the increased weight of relatively wide headers. It would also be desirable to provide such a mechanism that is capable of being retrofitted to existing combines in a cost effective manner. It would be desirable for such a mechanism to be adapted for use with a casting having side walls spaced slightly wider than the thickness of the framework that forms the notch for receiving the pivot pin.
The present invention provides a two piece retainer structure for securely confining a feederhouse pivot tube within a V-shaped notch defined in a combine frame structure. A first retainer piece is made of a polymer material and includes a relatively large arced portion that abuts a large area of the pivot tube. The first retainer piece is generally as wide as the side walls of the casting that holds the pivot tube, and therefore the first retainer abuts the pivot tube across a relatively wide area. A second retainer piece abut the first retainer piece and is coupled to the combine vehicle frame by way of a peg member positioned within an opening in the frame and a bolt member that secures the top portion of the second retainer piece to the combine frame.
The two-piece design of the retainer mechanism according to the present invention allows different materials to be utilized to thereby enhance the wear characteristics and generally allow the mechanism to resist wear better. The two piece retainer according to the present invention operatively abuts the pivot tube across a relatively large surface area to better transmit forces and to better resist friction and wear. The two piece retainer is adapted to be retrofitted to existing combines already in use which include a similar type of casting, pivot tube, V-shaped notch and attaching geometry.